Simulation experimental study on the coal blast mechanism

In order to improve the coal blast effect,the anthors analyzed the coal blast characteristics,and mechanism and selected the blast fracture criteria based on the rock blast theory.The simulation experimental results show that the stress wave contains two or more waveforms,and its decay rate is faster than it in general rock.The main effect of blast stress wave is forming a small number of new cracks,activating the native fracture,and breaking the balance of coal mine gas.The blast damage includes the initial phase of blast waves and the later stage of the detonation gas and coal mine gas,near the blast area,the damage decreases rapidly,but in the moderate or far area,the main reason of damage is detonation gas and coal mine gas,the damage decreases slowly.The numerical simulation results show the coal mine gas has a positive role in the process of coal blast.The coal blast broken is the result of the roles of the blast stress wave,detonation gas and coal mine gas.